When we go through a traumatic experience, immediate post-traumatic stress is natural. However, if this stress persists for months to years afterward, then we’re experiencing post-traumatic stress disorder (PTSD).

PTSD has serious implications for how it contorts our brains. While traumas will vary in degree, the brain experiences similar changes.

Most notably, your alarm system becomes extremely sensitive and prone to triggers. The alarm system is a natural necessity as it dictates survival. For example, if you see a tornado on the horizon, your alarm system will tell you to seek cover.

If you have PTSD, then your alarm systems kick in at seemingly random moments. In most cases, this alarm system recalls a traumatic event where survival was on the line and associates it with the present moment. ¹

Throughout this article, we’re going to take a deeper look into how PTSD changes your brain structure.

PTSD and the Brain: A Match Made in Hell

PTSD makes you prone to vivid flashbacks of a traumatic event that feel very real and threatening. These flashbacks usually occur when you experience a certain cue. ²

This cue is different for everyone but always relates to the traumatic event. For example, if you experience PTSD after a car accident where a red car hit you, red cars may trigger a traumatic response.

In turn, you may become avoidant from people, objects, or situations that can be a trigger. In many regards, it’s this avoidance behavior that makes PTSD such an unbearable condition to live with.

The problem with avoiding situations is you’re only fueling anxiety. When you choose not to participate, you tell your brain that the situation is bad. Going off the example of red cars, you may avoid going outside so as not to see red cars. This informs your brain that red cars are dangerous and your self-isolation is protective.

What you need to do is reverse these effects – to be able to go outside and come face-to-face with your triggers.

We’ve laid out how PTSD takes over your brain chemistry for this reason. We hope you use this information as a means of overcoming your traumatic event and PTSD symptoms.

The Hippocampus and Trauma

The hippocampus is a section in our brains that influences our limbic system. It’s responsible for new memories and growing our knowledge and emotions. ³

Studies have found that PTSD can significantly decrease the capacity of the hippocampus. As a result, the brain has a blurred perception of what is past and present. ⁴

Due to a reduced volume in hippocampus activity, your brain becomes much more vulnerable to triggers. For example, a rape victim may avoid public parks as the traumatic event occurred in this setting. Since the brain has difficulty separating the past from the present, the park brings the victim back into the presence of the traumatic event.

The Ventromedial Prefrontal Cortex and Trauma

A part of the prefrontal cortex, the ventromedial prefrontal cortex (vmPFC) is responsible for processing risks and fears. More importantly, the vmPFC regulates emotional responses caused by the amygdala. ⁵

PTSD results in a decreased volume of the vmPFC. In other words, it becomes more difficult to properly regulate emotions. As a result, you become more vulnerable to anxiety, fear, and stress – even when faced with a situation where these stimuli shouldn’t occur.

The vmPFC has this response partly due to the hippocampus’s difficulty in processing memory. Since new memories could reassure the vmPFC, the lack of these memories makes emotional processing even more of a challenge. ⁶

The Amygdala and Trauma

The amygdala is another part of the brain that plays a role in emotional processes. More specifically, it’s responsible for regulating fear. PTSD will leave you with a hyperactive amygdala.

Such hyperactivity occurs when you’re presented with a trigger to your traumatic event. However, interestingly, even when not faced with associations of the trauma, you may still exhibit increased stimuli in your amygdala. ⁷

If you find you’re always “on edge,” it’s likely due to increased amygdala activity. This is common in people who are vulnerable to panic attacks and other types of anxiety.

Final Word

The hippocampus, ventromedial prefrontal cortex, and amygdala all work together to regulate stress and fear. When one of these brain areas sees an increase in activity, the others follow suit in a domino effect.

A medical professional can help you to break this effect. In cases of PTSD, exposure therapy is usually the most helpful. You may also find relief from all-natural remedies or prescribed medications.

References

¹ Bremner JD. Traumatic stress: effects on the brain. Dialogues Clin Neurosci. 2006;8(4):445-61. doi: 10.31887/DCNS.2006.8.4/jbremner. PMID: 17290802; PMCID: PMC3181836.

² Mann SK, Marwaha R. Posttraumatic Stress Disorder. 2023 Jan 30. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. PMID: 32644555.

³ Rubin RD, Watson PD, Duff MC, Cohen NJ. The role of the hippocampus in flexible cognition and social behavior. Front Hum Neurosci. 2014 Sep 30;8:742. doi: 10.3389/fnhum.2014.00742. PMID: 25324753; PMCID: PMC4179699.

⁴ Sherin JE, Nemeroff CB. Post-traumatic stress disorder: the neurobiological impact of psychological trauma. Dialogues Clin Neurosci. 2011;13(3):263-78. doi: 10.31887/DCNS.2011.13.2/jsherin. PMID: 22034143; PMCID: PMC3182008.

⁵ Siddiqui SV, Chatterjee U, Kumar D, Siddiqui A, Goyal N. Neuropsychology of prefrontal cortex. Indian J Psychiatry. 2008 Jul;50(3):202-8. doi: 10.4103/0019-5545.43634. PMID: 19742233; PMCID: PMC2738354.

⁶ Weilbächer RA, Gluth S. The Interplay of Hippocampus and Ventromedial Prefrontal Cortex in Memory-Based Decision Making. Brain Sci. 2016 Dec 29;7(1):4. doi: 10.3390/brainsci7010004. PMID: 28036071; PMCID: PMC5297293.

⁷ Morey RA, Gold AL, LaBar KS, Beall SK, Brown VM, Haswell CC, Nasser JD, Wagner HR, McCarthy G; Mid-Atlantic MIRECC Workgroup. Amygdala volume changes in posttraumatic stress disorder in a large case-controlled veterans group. Arch Gen Psychiatry. 2012 Nov;69(11):1169-78. doi: 10.1001/archgenpsychiatry.2012.50. PMID: 23117638; PMCID: PMC3647246.